168
10.3 Life Cycle and Methods of Shiitake Cultivation
and Increasing Its Self-Life
The shiitake cultivation includes mycelial growth, formation of brown film, initiation of primordium, and fruiting body formation (Tang et al. 2013). The formation
of brown film formation is essential and unique for shiitake fruiting production. The
brown film formation includes the accumulation of pigments on older mycelial surface. The biofilm also maintains the water content in the growing medium, UV
radiation absorption, and protection to the inner mycelia and helps in higher production as well as quality (Belozerskaya et al. 2017; Yoo et al. 2019; Yan et al. 2020).
During this entire process, electron-dense material accumulates between the plasma
membrane and cell wall space and steadily also accumulates on the outside of the
cell wall which leads to cell wall stratification. The electron-dense material accumulated on the cell wall is similar to the primordium mycelial network (Butler and Day
1998; Vetchinkina et al. 2017). However, the variations on the deposition of electrondense materials in sawdust-containing medium were reported to be higher than
PDA and in mycelial tissues such as primordium or surface mycelium. The electron
microscopic-based studies revealed that melanin precursor is transported in lipid
vesicles and cytoplasmic vacuoles to the outside of cell wall (Butler and Day 1998;
Vetchinkina et al. 2017; Yan et al. 2020).
Shiitake belongs to division Basidiomycota, class Basidiomycetes, order
Agaricales, and family Agaricaceae (Wu et al. 2010). The genus is known to produce sexual basidiospores. Fruiting bodies known as basidiocarps contain the
basidiospore- producing structure called basidium (Terashima and Matsumoto
2004). Individual basidium contains four basidiospores each containing one haploid
nucleus. Basidiospores once released and get favorable conditions germinate, and
the hypha contains a single nucleus. The mycelium from a single spore cannot form
a fruiting body. It must pair with hypha from another spore of the opposite mating.
Hyphal tips fuse with each other to produce a small, compact dense ball-like compartment known as primordium (Bisen et al. 2010). It is small in size (0.5–1 mm)
and often buried as loose fuzzy mycelium in soil which is difficult to locate.
However, it contains the raw material required for the fruiting body formation. Once
the conducive conditions such as rainfall and appropriate temperature prevail, the
mycelial network collectively pumps nutrients and water into the primordium for its
rapid expansion which persists for a period of 12–96 h (Leatham 1982). After mating, the characteristic “fairy rings” are formed which give rise to mushrooms due to
prior exploration of nutrients over a large area. The formation of fruiting bodies
occurs in the older hyphae where nutrients are exhausted and there is scarcity
of food.
Lentinula edodes, known as wood-degrading fungi, is traditionally grown on
logs and sawdust-based materials. A combination of sawdust, wood wastes, and
straw or rice bran is also used for a large-scale production (Ohga and Kitamoto
1997: Yamanaka 1997). Under lab conditions, the pure culture of shiitake is maintained on potato dextrose agar (PDA) medium. However, economical and alternate
R. Salwan et al.
10.3 Life Cycle and Methods of Shiitake Cultivation
and Increasing Its Self-Life
The shiitake cultivation includes mycelial growth, formation of brown film, initiation of primordium, and fruiting body formation (Tang et al. 2013). The formation
of brown film formation is essential and unique for shiitake fruiting production. The
brown film formation includes the accumulation of pigments on older mycelial surface. The biofilm also maintains the water content in the growing medium, UV
radiation absorption, and protection to the inner mycelia and helps in higher production as well as quality (Belozerskaya et al. 2017; Yoo et al. 2019; Yan et al. 2020).
During this entire process, electron-dense material accumulates between the plasma
membrane and cell wall space and steadily also accumulates on the outside of the
cell wall which leads to cell wall stratification. The electron-dense material accumulated on the cell wall is similar to the primordium mycelial network (Butler and Day
1998; Vetchinkina et al. 2017). However, the variations on the deposition of electrondense materials in sawdust-containing medium were reported to be higher than
PDA and in mycelial tissues such as primordium or surface mycelium. The electron
microscopic-based studies revealed that melanin precursor is transported in lipid
vesicles and cytoplasmic vacuoles to the outside of cell wall (Butler and Day 1998;
Vetchinkina et al. 2017; Yan et al. 2020).
Shiitake belongs to division Basidiomycota, class Basidiomycetes, order
Agaricales, and family Agaricaceae (Wu et al. 2010). The genus is known to produce sexual basidiospores. Fruiting bodies known as basidiocarps contain the
basidiospore- producing structure called basidium (Terashima and Matsumoto
2004). Individual basidium contains four basidiospores each containing one haploid
nucleus. Basidiospores once released and get favorable conditions germinate, and
the hypha contains a single nucleus. The mycelium from a single spore cannot form
a fruiting body. It must pair with hypha from another spore of the opposite mating.
Hyphal tips fuse with each other to produce a small, compact dense ball-like compartment known as primordium (Bisen et al. 2010). It is small in size (0.5–1 mm)
and often buried as loose fuzzy mycelium in soil which is difficult to locate.
However, it contains the raw material required for the fruiting body formation. Once
the conducive conditions such as rainfall and appropriate temperature prevail, the
mycelial network collectively pumps nutrients and water into the primordium for its
rapid expansion which persists for a period of 12–96 h (Leatham 1982). After mating, the characteristic “fairy rings” are formed which give rise to mushrooms due to
prior exploration of nutrients over a large area. The formation of fruiting bodies
occurs in the older hyphae where nutrients are exhausted and there is scarcity
of food.
Lentinula edodes, known as wood-degrading fungi, is traditionally grown on
logs and sawdust-based materials. A combination of sawdust, wood wastes, and
straw or rice bran is also used for a large-scale production (Ohga and Kitamoto
1997: Yamanaka 1997). Under lab conditions, the pure culture of shiitake is maintained on potato dextrose agar (PDA) medium. However, economical and alternate
R. Salwan et al.